Of course, it is entirely arbitrary to adopt "0" and "1" as the symbols
for these two possible numbers. In Yi Jing, we use "broken line" and "solid line"
to represent the two numbers 0 and 1 respectively - like this:

0

1

In English, the name of the symbol "0" is "zero", and the name of the symbol "1" is "one."
In Ba Gua, the name of the symbol "0" in "ying", and the name of the symbol is "yang."

Furthermore, instead of calling these two symols "zero" and "one", we
may choose to call them "one" and "two", which we often do when we
speak of these as part of "digital numbers."

Using two binary digits, there are 4 possible numbers:

00
01
10
11

The Yi Jing symbol representations are:

00

01

10

11

The two binary numbers are place horizontally and should be read from left to right.
The Bagua numbers are placed on a vertical line, and should
be read from bottom up

Going up to three binary digits, there are 8 possible numbers:

000
001
010
011
100
101
110
111

These 8 numbers can be expressed in decimal system. We may choose to
use these 8 numbers to represent 0 to 7; or to repsent 1 to 8. See below:

000 0 1
001 1 2
010 2 3
011 3 4
100 4 5
101 5 6
110 6 7
111 7 8

Binary

Digital

Yi Jing symbol

Ba Gua Name

000

0

1

kun1

001

1

2

gen4

010

2

3

kan3

011

3

4

sun4

100

4

5

zhen

101

5

6

li2

110

6

7

dui1

111

7

8

qian2

This is what modern mathematicians call the "octal numbers" and Yi Jing
calls "Ba Gua."